Might have found a bug here, or maybe I'm doing something wrong. Last night I attempted to merge rojohounds example into my original project, and it refused to work. Eventually I stripped it back so that mine was basically event for event identical to the example, even down to the event ordering. At that point it miraculously began to work. This is keeping in mind that in rojohounds example, the target is the mouse pointer and in mine, the target was a sprite X/Y which was placed at the location of the mouse in the Always event.
Anyways, I thought Construct was just having a bit of a funny turn and left it. I was experimenting just now seeing if I could get a target to move in a restricted circle around my ship. The cap I've posted doesnt work. However, if you change the references to 'Target.x' and 'Target.y' in the set target position line to instead be mouse coordinates mousex and mouse y, it works (not properly but that's because I only just started playing with this)
See if anyone else has a problem
http://www.mediafire.com/?5q5kn9dsxp3gb92
It would seem that there's some problem working out an angle between two objects, but it''s fine when using an object and the mouse?